engine stuble with P0305...I'm stuck.

[dubs96q45]

My engine started stumbling on acceleration and at idle on Friday. The CEL came on Saturday. Discovered that it threw a P0305 code on Sunday when I got home and to my reader.

After a couple of hours of searching posts,I began by checking the injector resistances last night cool and warm this afternoon. They were all nearly identical both times. I didn't take note of the numbers because I thought I was eliminating the injectors as the culprits.

Moving on to the cylinder 5 plug and coil, I spent a little time busting my knuckles getting access to and removing them. The plug was pretty well blackened, not to mention not being the OEM NGK (my dad didn't see anything wrong with getting work done at Walmart when he owned it). Figured I might as well change all the plugs on this side at this point, so I installed the new one I had bought,and took it on a little road test to get three more. Seemed like it was not as bad as before, but still stumbling...CEL didn't come back on.

Decided to swap the 3 and 5 coils after installing all the new plugs. About 2 min after restarting the engine, it threw the P0305. Seemed like the stumbling had improved a bit more still, but who knows.

Seems to me like the problem is in cylinder 5 and its not the coil. Beyond that, I'm not sure what to make of it all.

Any idea what direction I should go next with it?

[Lokim]

Compression test the whole bank. Report back with results. Also, hook up a fuel pressure gauge and start the car, note fuel pressure. Turn off the car and see whether the pressure hold for at least 5 minutes. If pressure drops rapidly after shutdown, you likely have an injector leak, which is supported by the black plug (indicates running rich.)

[dubs96q45]

I've acquired the compression and fuel pressure equipment and was planning to do both today, only to realize that testing the fuel pressure is more complicated than I expected. I tried to to find a step-by-step or at least some more detailed info here and in the FSM , but have been so far unsuccessful. The kit has generic instructions, but there are a couple steps I could use a little guidance on.

The parts I am unsure about are:
-releasing the pressure
-the best/easiest possible location and procedure to attach the tee
-any Q45-specific details that might be important or helpful

Thanks

[Lokim]

1 - Pull the fuel pump fuse and start the car. Let it run until it stalls. Try to start it again, if it starts, let it stall again. If not proceed to 2.
2 - You'll need several inches of high-pressure fuel hose and two extra hose clamps. Detach the fuel line where it meets the rail, and put the spare hose and clamp on the fuel rail input. Tighten the clamp. Place the Tee in between the hose you just installed and the hose coming from the fuel filter. Install both hoses and clamps, tighten.
3 - Re-install the fuel pump fuse and start car. May take a couple tries for fuel to refill the injector rails and get the car started.

[Lokim]

You get it sorted out?